139557926621 has 2 divisors, whose sum is σ = 139557926622. Its totient is φ = 139557926620.

The previous prime is 139557926609. The next prime is 139557926623. The reversal of 139557926621 is 126629755931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 137845125625 + 1712800996 = 371275^2 + 41386^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-139557926621 is a prime.

It is a Sophie Germain prime.

Together with 139557926623, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (139557926623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69778963310 + 69778963311.

It is an arithmetic number, because the mean of its divisors is an integer number (69778963311).

Almost surely, 2^139557926621 is an apocalyptic number.

It is an amenable number.

139557926621 is a deficient number, since it is larger than the sum of its proper divisors (1).

139557926621 is an equidigital number, since it uses as much as digits as its factorization.

139557926621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6123600, while the sum is 56.

The spelling of 139557926621 in words is "one hundred thirty-nine billion, five hundred fifty-seven million, nine hundred twenty-six thousand, six hundred twenty-one".